Light emitting diodes (“LEDs”) are commonly used as light sources in various applications. The main functional part of an LED may be a semiconductor chip comprising two injecting layers of opposite conductivity types (p-type and n-type), and a light-emitting active layer for radiative recombination in which injection of carriers takes place. The semiconductor chip is usually placed in a package that provides electrical connections between the LED chip and the outside world, in addition to protection against vibration and mechanical shock.
LED packages can also play an important role in light collection. Specifically, LED packages can include a reflective layer formed underneath the packages' LED chip. The reflective layer may reflect light in one direction for increased luminous efficiency. However, reflective layers are often susceptible to corrosion due to exposure to moisture and corrosive small-molecule materials. When the reflective layer in an LED package is corroded, the light output efficiency of the LED package can be significantly reduced and the color of light produced by the LED package can change.
Accordingly the need exists for a new LED package design that protects reflective layers from corrosion due to exposure to moisture and/or other corrosive materials.